Apparatus for receiving signals

ABSTRACT

A radio or television receiver for receiving a plurality of signals, includes a selector for selecting a selected signal and a identifier for assigning an identity to each signal, e.g. a preset number. The receiver includes a history device for maintaining a list of identities of previously selected signals, a navigation device for traversing the list, and for selecting the signal corresponding to the identity at a current position.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a radio or television receiver for receiving aplurality of signals, comprising selection means for selecting aselected signal and identifying means for assigning an identity to eachsignal.

2. Description of the Related Art

Such a receiver is widely known. For example, a television receiver (orVCR) comprises tuning means for selecting a TV signal from a pluralityof TV channels. Similarly, a radio receiver can tune to a specific radiosignal. Such receivers often feature a mechanism for assigning anidentity to each channel for the purpose of displaying the selectedchannel, or enabling a user to select a particular channel. For example,preset numbers are used to identify a channel. The invention alsorelates to a television receiver comprising teletext means, enabling auser to select a particular page from a plurality of pages, each ofwhich is identified by a unique page number.

Often, users want to return to signals which were visited previously,e.g., when the user wants to match TV programs from a couple of channelsat the same time, or when some teletext pages comprise mutually relatedinformation. However, this is no trivial task with current radio andtelevision receivers. Users have to remember the identity of a signalthey will possibly want to return to in the future, and enter theidentity correctly when they actually want to return to the signal.There are TVs exist which offer the possibility to store identities in a‘favorite list’. However, this requires the user to perform explicitactions for storing and removing identities, and such lists need to beupdated regularly.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a radio or televisionreceiver which allows easy access to previously selected signals.

To achieve this object, the radio or television receiver according tothe invention is characterized in that the receiver further compriseshistory means for automatically keeping a history list of signalidentities in response to a succession of signal selections, the historymeans further comprising navigation means for changing a currentposition in the history list and generating a control signal for theselection means to select a signal corresponding to the identity at thecurrent position. Such history means automatically store identities ofsignals which have been selected recently, and enable the user to easilyrecall these signals.

In an embodiment, the history means are further adapted to impose anorder upon the history list, the navigation means further comprisingbackward means and/or forward means for changing the current position toa position which precedes or succeeds the current position in accordancewith the order. By imposing such an order on the identities in thehistory list, a simple mechanism can be applied to access all identitiesin the list, by consistently traversing the list in one or twodirections by means of said backward means and/or forward means. In apreferred embodiment, the signal identities in the history list aresubstantially ordered by ascending recency of storage in the historylist. In this way, the signals selected most recently are at the end ofthe list and can be selected with minimal effort by operating saidbackward means.

In a further embodiment, the history means further comprisediscrimination means for marking the selected signal as being relevantor irrelevant for including its identity in the history list, thehistory means being further adapted to include the identity of theselected signal only if the selected signal is marked as being relevant.By examining the selection behavior of the user, the history meansattempts to deduce whether a particular signal is of current interest tothe user, i.e., relevant for including its identity in the history list.Filtering less relevant signals from the history list further enhancesthe usability of the history means. Various embodiments, definingconditions for signals to be included in the history list, will now bedisclosed.

TV channels or teletext pages which have been selected for somepredetermined period of time are likely to be of current interest to theuser, hence, in an embodiment, they are included in the history list. Ina further embodiment, also channels which are selected by explicitlyentering their identity, as opposed to zapping, are included in thehistory list. Most radio or television receivers impose a logical orderon the identities of the plurality of signals and provide zapping meansfor traversing the identities in an ascending or descending direction.For example, presets are often assigned numbers, and said zapping meansare generally implemented by an ‘up’ button and a ‘down’ button, whichselect a channel or a teletext page whose number is increased ordecreased by one with respect to the number of the currently selectedchannel or page. Zapping through radio or TV channels is typicallyperformed when the user has no specific intentions or expectations, somost channels selected this way are not likely to be of much interest tothe user. In a radio or television receiver according to the invention,signals which are selected by means of the zapping means are notincluded in the history list, unless they have been inspected for saidpredetermined period of time.

In a further embodiment, which is particularly useful for teletext, asignal is included in the history list when it was displayed whenanother signal was selected by explicitly entering its identity. In ateletext system, this guarantees that index pages, comprising numbers ofother pages which are likely to be entered explicitly by the user, areincluded in the history list, hence can be recalled easily.

A further condition for including an identity of a channel or teletextpage in the history list is the operation of the navigation means whenthe channel or page is currently displayed. This guarantees that thechannel or page can also be returned to by means of the navigationmeans. Optionally, the identity can be removed again after returning toit by means of the navigation means.

It is to be noted that television receivers are known which feature adedicated button for selecting the previous channel. There are alsotelevision receivers which feature colored buttons for recalling twopreviously selected teletext pages which are indicated on the screen incorresponding colors. A drawback of such a feature is that only a verylimited number of signals can be accessed and that disturbing elementsare required on the screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a television receiver comprising history meansfor recalling previously selected channels;

FIG. 2 shows a flow chart of the behaviour of the history means; and

FIG. 3 shows a flow chart of an alternative way of storing a signalidentity in the history list.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a television receiver according to the invention,comprising an antenna 101 for receiving TV signals from the atmoshphereor from a cable network. Tuning means 102 select one of the receivedsignals and split the signal into an audio signal and a video signal,the audio signal being further processed by an audio processor 103 and aloudspeaker 104, and the video signal being further processed by a videoprocessor 105 and a display screen 106. Control means 107 generatecontrol signals for the tuning means 102, the control signalsdetermining which channel is selected by the tuning means 102. Thecontrol means 107 comprise preset means 108, zapping means 109, historymeans 110 and input means 115. The input means 115 enable a user tocontrol the preset means 108, the zapping means 109, and the historymeans 110. The history means 110 comprise navigation means 113 anddiscrimination means 114. The navigation means 113 comprise backwardmeans 111 and forward means 112. The input means 115 comprise a remotecontrol unit accommodating up/down means 116, numerical means 117, a‘backward’ button 118 and a ‘forward’ button 119. The ‘backward’ button118 and the ‘forward’ button 119 are distinct from the up/down means 116and serve another purpose, as will be explained later.

The preset means 108 assigns an identity to a subset of the receivedTV-channels in the form of a number in a certain range, e.g., from ‘1’to ‘99’. The user can operate the numerical means 117 to enter a presetnumber. Selecting a preset causes the tuning means 102 to tune to the TVchannel to which that preset is assigned. Alternatively, presets can beselected by means of the zapping means 109. The zapping means 109 can becontrolled by the up/down means 116, which normally comprises an ‘up’button and a ‘down’ button. If the ‘down’ button is pressed, the zappingmeans 109 take the currently selected preset number and control thepreset means 108 to select the preset preceding the currently selectedpreset. For example, if preset ‘20’ is currently selected, pressing the‘down’ button would select preset ‘19’. Similarly, pressing the ‘up’button would select preset ‘21’. The preset means 108 and the zappingmeans 109 are known per se and are widely applied in radio andtelevision receivers.

Presets can also be selected by means of the history means 110, whichkeep a record of previously selected presets. These presets can berecalled by operating the ‘backward’ button 118 which controls thebackward means 111, or the ‘forward’ button 119 which controls theforward means 112. The previously selected presets are stored in ahistory list, and ordered in accordance with their recency of storage.Pressing the ‘backward’ button 118 causes a ‘current position’ to shiftone position into the direction of the first position in the historylist, and select the corresponding preset. Pressing the ‘forward’ button119 causes the position to shift one position into the direction of thelast position in the history list, and select the corresponding preset.In this way, the history list can be traversed, and previously selectedpresets can be recalled. Presets which are selected via the historymeans 110 are not stored again in the history list, because they arealready present in the history list, at the position which is indicatedby the current position. The discrimination means 114 serve to assign astatus to a selected preset, this status marking the selected preset asbeing relevant or irrelevant for storing its number in the history list.The decision about the status is based on various conditions, e.g.,related to the way the preset was selected. Several embodiments of thehistory means 110 are possible, which differ in their behavior withrespect to storing preset numbers in the history list, removing presetnumbers from the history list, the exact order of preset numbers, etc.

FIG. 2 shows a flowchart of the behaviour of one embodiment of thehistory means. The following variables are introduced for describing astate of the television receiver:

Sel: represents the currently selected preset,

Len: represents the length of the history list, i.e., the number ofidentities in the list,

Pos: represents the current position within the history list.

The discrimination process carried out by the discrimination means 114is roughly described by steps 202 to 206 and step 210.

In an initial step 201, actions are included which are performed atpower-on. Sel is set to 1, which means that the preset with number ‘1’is selected initially. Len is set to 0, which means that initially, thehistory list is empty. Pos is set to 0, which means that there is nocurrent position in the history list. In steps 202 to 206, tests areperformed for detecting certain conditions. If the tests have asuccessful result, steps are performed which can be reached by followingthe arrows marked ‘Y’. If the tests fail, a subsequent test is performedby following the arrows marked ‘N’. The order in which the tests areperformed is not critical. In practice, they are likely to beimplemented in an event-driven way, triggering steps as soon as somecondition is satisfied and avoiding the need to perform the steps 202 to206 cyclically.

The test in the step 203 succeeds if the user enters a preset number Numby means of the numerical means 117. This event causes step 208 and 216to be performed consecutively. In the step 208, Sel gets the value Num,which means that the preset is selected which corresponds to the numberentered. The test in the step 216 succeeds if the currently selectedpreset corresponds to the preset at the current position in the historylist. If the test in the step 216 fails, step 211 is performed. In thestep 211, the newly selected preset is appended to the history list,after removing all preset numbers following the current position forreasons which will be explained hereinafter. This is achieved byincreasing Pos by 1, storing the number of the newly selected preset atthe location indicated by Pos, and making Len equal to Pos. If thecurrent position was already at the last element of the history list, nopreset numbers need to be removed and the newly selected preset issimply appended to the history list. If the test in the step 216succeeds, no further action is performed, because appending the newlyselected preset to the history list would yield two identical presetnumbers in succession.

Other conditions may cause a newly selected preset not to be stored inthe history list, because it is assumed that these conditions render apreset less likely to be recalled later. For example, the test in thestep 202 succeeds if the user operates the zapping means 109 by means ofthe up/down means 116 to select a preset which precedes or succeeds thecurrently selected preset. If this is the case, the newly selectedpreset number is not stored in the history list. Only preset numbersfollowing the current position are removed from the history list in step207, for reasons which will be explained hereinafter. It is assumed thata preset which was selected with the zapping means 109, is generally notof particular interest to the user.

The test in step 204 succeeds as soon as a preset has been selected fora predetermined consecutive period of time, e.g., five minutes. If thatis the case, the step 216 is performed, and if it fails, the presetnumber is appended to the history list in the step 211 as describedabove. Effectively, the test in the step 204 causes only presets whichare selected by means of the zapping means 109 to be included in thehistory list, because in all other cases the test in the step 216succeeds and no further action is performed.

Hence, newly selected presets are stored in the history list if theywere selected explicitly by means of the numerical means 117 or if theywere selected by means of the up/down means 116 and have been selectedfor a predetermined period of time . This is based on the assumptionthat these conditions render a preset likely to be recalled later.

The test in step 205 succeeds if the user operates the backward means111 by means of the ‘backward’ button 118. If this is the case, the testin step 213 is performed, checking whether the current position Pos isgreater than one. If this is the case, the test in step 210 is performedfirst, checking whether the currently selected preset corresponds to thepreset at the current position in the history list. This is the case ifthe currently selected preset is not selected by means of the zappingmeans 109. If the test in step 210 succeeds, step 214 is performed,decreasing Pos by one and selecting the corresponding preset, indicatedby Sel=His [Pos], thus recalling a preset which was originally selectedbefore the currently selected preset. If the test in the step 210 fails,step 215 is performed first before performing step 214.

The step 215 is identical to the step 211, appending the currentlyselected preset to the history list, after removing all preset numbersfollowing the current position. Thus the preset is stored in the historylist, although the preset was selected by means of the zapping means109.

The test in the step 206 succeeds if the user operates the forward means112 by means of the ‘forward’ button 119. If this is the case, the testin step 209 is performed, checking whether the current position Pos issmaller than the length of the history list, hence not pointing to thelast element in the history list. If the test in the step 209 succeeds,the current position Pos is increased by one, and the correspondingpreset is selected, indicated by Sel=His [Pos].

In summary, newly selected presets are stored in the history list ifthey were selected explicitly by means of the numerical means 117 or ifthey were selected by means of the up/down means 116 and have beenselected for a predetermined period of time. The backward means 111 andthe forward means 112 enable a user to traverse the history list in twodirections by increasing or decreasing the current position, andselecting the preset at the new current position. When the user operatesthe zapping means 109, the current position remains unchanged, butpreset numbers following the current position are removed from thehistory list, which disables the forward means 112 because of the testin the step 209. Operating the forward means 112 would not make sense,because the user would stop traversing the history list by operating thezapping means 109. The backward means 111 can still be used to recallthe preset at the current position. The newly selected preset is notstored in the history list. Only after operating the backward means 111is the preset stored in the history list as yet, in order to enable theuser to reselect the preset by means of the forward means 112.

Only two additional buttons, i.e., the ‘backward’ button 118 and the‘forward’ button 119, are required for implementing the functionalitydescribed. In a further embodiment, a third button could be added fordisplaying the history list on the television screen, enabling the userto select a preset by picking a preset from the history list, similarlyto the widely applied on-screen menus. After picking a preset, thecurrent position is set to the preset position in the history list.

The history list could grow indefinitely, so measures have to be takento avoid memory overflow. A good solution is to ‘forget’ about presetsselected a relatively long time ago, by removing presets at the start ofthe history list. Another measure is to avoid double occurrences byremoving existing occurrences of a newly stored preset.

Various variants are conceivable, which differ in their behavior withrespect to storing preset numbers in the history list, removing presetnumbers from the history list, the exact order of preset numbers, etc.In the variant described, the history list is truncated after thecurrent position when a new preset has to be stored in the history list,or when the user operates the zapping means 109. This guarantees thatthe original order of selection is preserved, which is particularlyadvantageous for teletext pages where there is often a meaningfulrelationship between successively selected pages. However, adisadvantage is that some signal identities are removed from the historylist, hence cannot be recalled easily.

Instead of removing presets from the history list, newly stored presetscould be simply inserted after the current position, enabling theforward means 112 even for newly stored presets. For example, if thehistory list is given by [1,3,5], the current position being underlined,and preset ‘6’ is selected by entering ‘6’ with the numerical means 117,the new history list would be [1,3,6,5]. In another variant, newlystored presets are appended at the end of the history list. In thisvariant, it could be convenient to partially reorder the presets in thehistory list, to obtain an intuitive behavior of the backward means 111.For example, the resulting history list in the example could be[1,5,3,6], and the backward means 111 would select preset ‘3’ asexpected. This variant is easily obtained by removing ‘Len=Pos’ from thestep 207 of FIG. 2 and by replacing the steps 211 and 215 by theflowchart shown in FIG. 3. The test in step 301 fails if the currentposition is at the last element of the history list, in which case thecurrently selected preset is simply appended to the history list asperformed by step 305. If the test in step 301 succeeds, a loopconstituted by steps 302, 303 and 304 is performed, after which thesublist starting at the current position and ending at the last positionis reversed. An auxiliary variable ‘i’ gets an initial value ‘0’ in thestep 302. In the step 303, each time two opposite elements areexchanged, starting at the elements at the current position and the lastelement, and proceeding inwardly controlled by the variable ‘i’ which isincreased by one repeatedly. If the middle of the sublist is reached,which is tested in the step 304, the loop ends.

All variants could be applied equally well to presets of a radioreceiver, or to teletext pages. For teletext, a slightly differentapproach could be adopted, i.e., including a page in the history listwhich was displayed when another page was selected by explicitlyentering its number. This guarantees that index pages, comprisingnumbers of other pages which are likely to be entered explicitly by theuser, are included in the history list, and hence, can be recalledeasily by means of the backward means 111. The explicitly selected pagesthemselves could be left out of the history list, as opposed to thevariant of FIG. 2, as well as pages which have been selected for apredetermined period of time.

In a further embodiment, the history means are entirely incorporated ina control apparatus, e.g., a remote control unit for a televisionreceiver. Incorporating the history means in a universal remote controlunit enables the functionality of existing equipment to be extended witha history function according to the invention at very low cost. Theremote control unit comprises numerical input means, e.g., for enteringpreset or page numbers, and zapping means, e.g., an ‘up’ button and a‘down’ button, for increasing or decreasing the last input number byone. The remote control unit further comprises means for adapting theinterpretation of entered digits to the remote-controlled apparatus.Various approaches are known for distinguishing between separate digitsand complete numbers. For example, a user is asked to specify beforehandwhether a single digit or double digit number will be entered.Alternatively, digits which are entered within a certain period of timeare considered to belong to one number. The controlled apparatus and theremote control unit should interpret entered digits in the same way. Theremote control unit further comprises history means, for example asdescribed above and depicted in FIGS. 2 and 3. The history means keep ahistory list of numbers which are explicitly entered. If, after azapping operation, no relevant actions are performed for a certainperiod of time, the history means store a number in the history listwhich is derived from the most recent number and subsequent zappingoperations. For example, if subsequently to entering a number ‘12’, isentered, the ‘up’ button is pressed twice and the ‘down’ button ispressed once, and then no further action is performed during apredetermined time interval, while the number ‘13’ is stored in thehistory list. The remote control unit further comprises ‘backward’ and‘forward’ buttons for traversing the history list as describedhereinbefore, causing the number at the current position to betransmitted.

What is claimed is:
 1. A radio or television receiver for receiving aplurality of signals, comprising: selection means for selecting aselected signal from said plurality of signals; and identifying meansfor assigning an identity to each signal of said plurality of signals,characterized in that the receiver further comprises: history meanscomprising memory means for storing, automatically, a history list ofsignal identities in response to a succession of signal selections,navigation means for changing a current position in the history list andgenerating a control signal for the selection means to select a signalcorresponding to the signal identity at the current position, andwherein the discrimination means are further adapted to mark theselected signal as being relevant if it has been selected for at least apredetermined period of time or it has been selected by explicitlyentering its identity, regardless of the time viewed.
 2. A radio ortelevision receiver as claimed in claim 1, characterized in that thehistory means further comprises means for imposing an order upon thehistory list in said memory means, the navigation means furthercomprising backward means and/or forward means for changing the currentposition to a position which precedes or succeeds the current positionin accordance with the order.
 3. A radio or television receiver asclaimed in claim 2, characterized in that the signal identities in thehistory list are substantially ordered by ascending recency of storagein the history list.
 4. A radio or television receiver as claimed inclaim 1, wherein the receiver further comprising input means forentering a signal identity and for selecting the corresponding signal,characterized in that the discrimination means marks the selected signalas being relevant if a further signal is selected by means of the inputmeans.
 5. A radio or television receiver as claimed in claim 1,characterized in that the discrimination means marks the selected signalas being relevant if a further signal is selected by the navigationmeans.
 6. A radio or television receiver as claimed in claim 1,characterized in that the plurality of signals are radio or televisionchannels, and the identities are preset numbers.
 7. A televisionreceiver as claimed in claim 1, characterized in that the plurality ofsignals are teletext pages, and the identities are page numbers.